Bleeding brakes

[PJR2601]

I have changed all the brake cylinders and shoes on my '71 Traveller. I'm having great difficulty in bleeding the brakes so that the system works well; still having to pump the pedal to get any pressure on the brakes and stop . The handbrake is coming into it's own!!

Some help/advice would be most welcome as it has been a time consuming job and just want to get out on the road and enjoy the summer

Thank you

Peter Raybaud

[svenedin]

A few additional details would be helpful.

Is this a standard system? Drums all round, no servo?

What method have you used to bleed the brakes so far? Have you followed the sequence as described in the workshop manual (i.e longest pipe run first)? Have you adjusted the brakes to lock the drums and then backed off by one click on the adjuster? It may be necessary to do this again now that the system is bled and the shoes have fully centralised.

Does the brake pedal feel spongy or does it slowly creep towards the floor? The former is air, the latter is a fluid leak. A pedal that is long (seems to travel a long way until the brakes are effective but feels normal) is an adjustment issue.

It is worth noting that it is very important to make sure that the fluid reservoir in the master cylinder does not drop less than 50% or so (this is a safe margin). If the level drops too low air gets drawn in and you have to start bleeding the brakes all over again.

Sometimes the seal is damaged in the master cylinder when bleeding the brakes. This is due to the seal going past a wear lip in the bore and getting torn. In such circumstances the only option is a new master cylinder. This is why many owners use pressure bleeding with the Eezibleed system but it is not as simple as just buying the kit, you also need to get an unvented master cylinder cap and modify it to accept the Eezibleed fitting. Other owners rate vacuum bleeding but I have never tried it so cannot comment on how well it works.

Stephen

[myoldjalopy]

"Sometimes the seal is damaged in the master cylinder when bleeding the brakes. This is due to the seal going past a wear lip in the bore and getting torn. In such circumstances the only option is a new master cylinder."
This is a possibility - it happened to me once. I tried bleeding several times without success and, like the OP, had to pump the pedal to get braking. Even my go-to garage couldn't get a good pedal and they suggested the master cylinder might have failed. In desperation, I got them to fit a new MC and problem solved.

[PJR2601]

It is drums all round

No servo

I seem to be following all the "recommendations" but still find it not working and the pedal has to be pumped 2/3 times before we get any pressure on the brakes

HELP!!!

[svenedin]

It is drums all round

No servo

I seem to be following all the "recommendations" but still find it not working and the pedal has to be pumped 2/3 times before we get any pressure on the brakes

HELP!!!

In that case, if it's not air or adjustment it's the master cylinder and that unfortunately is not an easy job to change.

Stephen

[mowogg]

Before you do anything further have you checked for leaks?

Did you replace all the copper washers on the cylinders?

[svenedin]

Before you do anything further have you checked for leaks?

Did you replace all the copper washers on the cylinders?

Good idea. Go around and wipe all of the joints to see if they are wet. If in doubt jam a piece of wood between the front of the seat and the brake pedal, putting pressure on the brake pedal. Leave overnight. If the piece of wood has fallen out because the brake pedal has slowly crept down there is a leak somewhere. Or, use the Eezibleed brake bleeding system. The pressure soon shows up leaks! I have personally found leaks this way.

Stephen

[Bill_qaz]

Before you do anything further have you checked for leaks?

Did you replace all the copper washers on the cylinders?

Good idea. Go around and wipe all of the joints to see if they are wet. If in doubt jam a piece of wood between the front of the seat and the brake pedal, putting pressure on the brake pedal. Leave overnight. If the piece of wood has fallen out because the brake pedal has slowly crept down there is a leak somewhere. Or, use the Eezibleed brake bleeding system. The pressure soon shows up leaks! I have personally found leaks this way.

Stephen

Or if the wood drops out with no external leaks, including the master cylinders push end. Then its the master cylinder internally bleeding pressure back to resevoir.

[svenedin]

Before you do anything further have you checked for leaks?

Did you replace all the copper washers on the cylinders?

Good idea. Go around and wipe all of the joints to see if they are wet. If in doubt jam a piece of wood between the front of the seat and the brake pedal, putting pressure on the brake pedal. Leave overnight. If the piece of wood has fallen out because the brake pedal has slowly crept down there is a leak somewhere. Or, use the Eezibleed brake bleeding system. The pressure soon shows up leaks! I have personally found leaks this way.

Stephen

Or if the wood drops out with no external leaks, including the master cylinders push end. Then its the master cylinder internally bleeding pressure back to resevoir.

Yes good point. Morris Minor Workshop recommended to me this piece of wood technique so it is well tried and tested. If it is a master cylinder problem it is not usually possible to rebuild them at home if the bore is worn or corroded.

Stephen